(1) Field of the Invention
The present invention relates to a reactive energy compensator that can be electrically connected to an alternating electrical network.
(2) Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98.
A reactor energy compensator can be electrically connected to an alternating electrical network including M phase(s), M being an integer greater than or equal to 1, the compensator comprising:    M connection terminals for connecting to the alternating network,    N banks of capacitor(s) capable of providing reactive energy, N being an integer greater than or equal to 2,    N two-way voltage inverters, connected to each other in parallel and each connected to a unique capacitor hank, each inverter being able to convert a direct current into an alternating current including M phase(s) in one direction and the alternating current into direct current in the other direction, each inverter including first and second input terminals and M output terminal(s), the input terminals being connected to the corresponding capacitor bank, each output terminal corresponding to a phase of the alternating current and being connected to a corresponding connection terminal,    a device for balancing the voltage of the N capacitor banks.
A reactive energy compensator of the aforementioned type is known. The reactive energy compensator comprises polyphase inverters connected to each other in parallel, each inverter being bidirectional, electrically connected in input to a unique capacitor bank capable of supplying reactive energy and electrically connected in output to the alternating network. Such a reactive energy compensator makes it possible to reduce any disruptions of the alternating network due to a disrupting charge connected to the network, such as an arc furnace. The compensator comprises control means for controlling the voltage inverters according to a control law, and the voltage of each capacitor bank is balanced by means of the control of the voltage inverters.
However, when the disruptions of the alternating network are significant, the control using the control means of the voltage inverters no longer makes it possible to balance the voltage of each capacitor bank. Voltage unbalances then appear between the different capacitor banks, which then creates a divergence of the voltages of the different capacitor banks, and requires that the reactive energy compensator be stopped.